Information recording medium, apparatus and method for performing after-recording on the recording medium

ABSTRACT

The invention provides an information recording medium such as an optical disk, having a large capacity and being capable of performing read/write operations at high speeds. The recording medium includes audio stream prepared for after-recording data, and a audio attribute information having a bit rate information to the recorded audio stream as a management information. A recorder according to the invention has a check unit for checking, in advance, the possibility of after-recording operation of the recorder to the audio stream to be after-recorded with reference to the bit rate information of the audio attribute information.

This is a divisional application of Ser. No. 09/504,938 filed Feb. 16,2000, now U.S. Pat. No. 6,374,037 B1.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an information recording medium like anoptical disc which has large capacity and to/from which data arewritten/ read in high speed, and more particularly to a recording mediumwhich can perform after-recording, an apparatus and a method forrecording thereto.

2. Related Art

In the field of a writable optical disc having an upper bound ofapproximately 650 MB, a phase change type disc DVD-RAM having a capacityof several GB has appeared. Moreover, in addition to the practical useof MPEG (MPEG2) which is the coding standard of digital AV data, theDVD-RAM has been expected as recording and reproducing media in the AVfield as well as computer application. In other words, it is expectedthat the DVD-RAM will spread as media in place of a magnetic tape whichis conventionally typical AV. recording media.

(Description of DVD-RAM)

In recent years, an enhancement in the density of a writable opticaldisc has been developed so that it has been possible to record videodata as well as computer data and audio data.

For example, a convexo-concavo shaped guide groove has conventionallybeen formed on the signal recording face of the optical disc. While asignal has conventionally been recorded on only a land portion or agroove portion, it has become possible to record the signal on both theland and groove portions by a land-groove recording method.Consequently, a recording density has been enhanced by approximatelytwice as much (see Japanese Patent Laid-Open Publication No. 8-7282, forexample). Moreover, there has also been devised and practically used azone CLV method or the like in which the control of a CLV method(constant linear velocity recording) effective in an enhancement in therecording density can be simplified and easily used practically (seeJapanese Patent Laid-Open Publication No. 7-93873, for example).

Significant problems in the future are how to record AV data includingvideo data using an optical disc intended to have an increase in acapacity, and how to implement performance greatly exceeding aconventional AV apparatus and new functions.

By the appearance of such a writable optical disc having a largecapacity, it can be supposed that an optical disc becomes a mainstreamalso for AV recording and reproduction in place of a conventional tape.The conversion of recording media from the tape into the disc hasvarious influences on the function and performance of an AV apparatus.The conversion into the disc has the greatest feature that random accessperformance is considerably enhanced. If the tape is subjected to randomaccess, it is necessary to usually take a time in order of severalminutes for one rewinding. This is extraordinarily late as compared witha seek time (20-60 ms or less) on the optical disc media. Accordingly,the tape cannot act as a random access device in respect of practicaluse. By such random access performance, the distributed recordingoperation of the AV data which could not be performed by theconventional tape can be implemented by the optical disc.

FIG. 34 is a block diagram showing a drive device of a DVD recorder. Inthe drawing, the reference numeral 11 denotes a optical pick-up forreading the data of a disc, the reference numeral 12 denotes an ECC(error correcting code) processing section, the reference numeral 13denotes a track buffer, the reference numeral 14 denotes a switch forswitching the input and output to and from the track buffer, thereference numeral 15 denotes an encoder, and the reference numeral 16denotes a decoder. The reference numeral 17 denotes a enlarged part ofthe disc.

As shown by the reference numeral 17, data are recorded on the DVD-RAMdisc with 1 sector=2 KB as a minimum unit. Moreover, an error correctingprocessing is executed by the ECC processing section 12 with 16sectors=1 ECC block.

The track buffer shown by the reference numeral 13 serves to record theAV data with a variable bit rate in order to record the AV data on theDVD-RAM disc more efficiently. While a read/write rate (Va in thedrawing) from/to the DVD-RAM is a fixed rate, the AV data change a bitrate (Vb in the drawing) according to the complexity of the contentsthereof (a video image, for example). The track buffer 13 serves toabsorb a difference in the bit rate. For example, this is not requiredif the AV data is set to the fixed bit rate as in a video CD.

By utilizing the track buffer 13 still effectively, the AV data can bediscretely provided on the disc. Description will be given withreference to FIG. 35.

FIG. 35A is a diagram showing an address space on a disc. In the casewhere the AV data are separately recorded in a continuous region of [a1,a2] and a continuous region of [a3, a4] as shown in FIG. 35A, the AVdata can be continuously reproduced by supplying data stored in thetrack buffer 13 to the decoder 16 while a seek is being carried out froma2 to a3. A status obtained at this time is shown in FIG. 35B.

The AV data read from a1 are input to the track buffer 13 and outputfrom the track buffer 13 at a time t1, and the data are stored in thetrack buffer 13 by a rate difference (Va−Vb) between an input rate (Va)to the track buffer 13 and an output rate (Vb) from the track buffer 13.This state continues up to a2 (time t2). When an amount of data storedin the track buffer 13 for this period of time is represented by B (t2),it is sufficient that amount B (t2) stored in the track buffer 13 can beconsumed to be continuously supplied to the decoder 16 until a time t3corresponding to data reading start point of a3.

In other words, if a constant amount of data to be read before the seekor more are kept, the AV data can be continuously supplied even if theseek is generated.

In the above example the description is given to the case where the dataare read from the DVD-RAM (that is, playback), however the case wherethe data is written to the DVD-RAM (that is, picture recording) may beconsidered similarly.

If the constant amount or more of data are continuously recorded on theDVD-RAM as described above, continuous reproduction/picture recordingcan be carried out even if the AV data are distributed and recorded onthe disc.

(Description of MPEG)

Next, description will be given to the AV data.

As described earlier, the AV data to be recorded on the DVD-RAM use aninternational standard referred to as MPEG (ISO/IEC13818).

Even a DVD-RAM having a large capacity of several GBs does not alwayshave a sufficient capacity for exactly recording non-compressed digitalAV data. Therefore, a method for compressing and recording the AV datais required. As a method for compressing the AV data, the MPEG(ISO/IEC13818) has widely spread in the world. In recent years, the LSItechnology has been improved so that MPEG codec (expansion/compressionLSI) has been put into practical use. Consequently, the DVD recorder canimplement MPEG expansion/compression.

The MPEG mainly has the following two features in order to implementhighly efficient data compression.

A first feature is that a compressing method using a time correlationcharacteristic between frames is introduced in addition to a compressingmethod using a space frequency characteristic which has conventionallybeen carried out in the compression of the motion picture data. In theMPEG, each frame (which will be also referred to as a picture in theMPEG) is classified into three kinds of parts, that is, an I picture(intra-frame coding picture), a P picture (a picture using theintra-frame coding and a reference relationship in the past) and a Bpicture (a picture using the intraframe coding and referencerelationships in the past and future), thereby performing datacompression.

FIG. 36 is a diagram showing a relationship among the I, P and Bpictures. As shown in FIG. 36, the P picture refers to the last I or Ppicture in the past, and the B picture refers to the closest I or Ppicture in the past and future. As shown in FIG. 36, moreover, since theB picture refers to the I or P picture in the future, the display order(display order) of each picture and the order (coding order) on thecompressed data may be coincident with each other.

A second feature of the MPEG is that coding amount can be assigneddynamically for each picture in accordance with the complexity of thepicture. The decoder of the MPEG comprises an input buffer. The decodercan assign a large coding amount to a complex picture which is hard tocompress by storing data in the decoder buffer in advance.

Audio data used by the DVD-RAM can be selected for use from three kindsof parts, that is, MPEG audio for carrying out data compression, Dolbydigital (AC-3) and non-compressed LPCM. While the Dolby digital and theLPCM have a fixed bit rate, the MPEG audio has a variable bit rate andhas a size which is not as great as the size of a video stream but canbe selected from plural kinds of sizes in an audio frame unit.

Such AV data are multiplexed into one stream by a method referred to asan MPEG system. FIG. 37 is a diagram showing the structure of the MPEGsystem. The reference numeral 41 denotes a pack header, the referencenumeral 42 denotes a packet header, and the reference numeral 43 denotesa payload. The MPEG system has a hierarchical structure which isreferred to as a pack and a packet. The packet comprises the packetheader 42 and the payload 43. The AV data are divided per proper sizefrom the head, and are stored in the payload 43. The packet header 42stores ID (stream ID) for identifying stored data, a decoding time DTS(Decoding Time Stamp) of data (the DTS is omitted if the decoding andthe display are carried out at the same time as in the audio data) and apresentation time PTS (Presentation Time Stamp) of the data which areincluded in the payload represented with a precision of 90 kHz arerecorded, as information related to AV data stored in the payload 43.The pack is a unit having a plurality of packets together. In case ofthe DVD-RAM, one pack is used every packet. Therefore, the packcomprises the pack header 41 and the packet (the packet header 42 andthe payload 43). The pack header stores SCR (System Clock Reference)representing with a precision of 27 MHz a time that data in the pack areinput to the decoder buffer.

In the DVD-RAM, such an MPEG system stream is recorded by using one packas one sector (=2048 B).

Next, description will be given to a decoder for decoding theabove-mentioned MPEG system stream. FIG. 38 shows a decoder model(PS-TD) of the MPEG system decoder. The reference numeral 51 denotes anSTC (System Time Clock) acting as a reference time in the decoder. Thereference numeral 52 denotes a demultiplexer for decoding ordemultiplexing a system stream. The reference numeral 53 denotes aninput buffer of a video decoder. The reference numeral 54 denotes avideo decoder. The reference numeral 55 denotes a reorder buffer fortemporarily storing the I and P pictures to absorb a difference betweenthe data order and the display order which is made between the I and Ppictures and the B picture as described above. The reference numeral 56denotes a switch for adjusting the order of the outputs of the I and Ppictures stored in the reorder buffer and the B picture. The referencenumeral 57 denotes an input buffer of an audio decoder. The referencenumeral 58 denotes an audio decoder.

Such an MPEG system decoder serves to process the abovementioned MPEGsystem stream in the following manner. At a time that the time of theSTC 51 is coincident with the SCR described in the pack header, thedemultiplexer 52 inputs the same pack. The demultiplexer 52 serves tointerpret a stream ID in the packet header and to transfer the data ofthe payload to the decoder buffer for each stream. Moreover, thedemultiplexer 52 fetches the PTS and the DTS in the packet header. Thevideo decoder 54 fetches picture data from the video buffer 53 at a timethat the time of the STC 51 is coincident with the DTS to carry out adecode processing, and stores the I and P pictures in the reorder buffer55 and displays the B picture. While the I and P pictures are decoded bythe video decoder 54, the switch 56 is connected to the reorder buffer55 to output a previous I or P picture in the reorder buffer 55. Whilethe B picture is decoded, the switch 56 is connected to the videodecoder 54. The audio decoder 58 fetches and decodes data for one audioframe from the audio buffer 57 at a time that the time of the STC 51 andthe PTS (there is no DTS in cast of audio) are coincident with eachother in the same manner as the video decoder 54.

Next, description will be given to a method for multiplexing the MPEGsystem stream with reference to FIGS. 39A-39D. FIG. 39A shows a videoframe, FIG. 39B shows a status in the video buffer, FIG. 39C shows theMPEG system stream, and FIG. 39D shows audio data. An axis of abscissaindicates a time base which is common to each drawing, and each drawingis represented on the same time base. As shown in FIG. 39B, moreover, anaxis of ordinate indicates a buffer usage (the data storage amount ofthe video buffer), and a thick line in the drawing indicates atransition of the buffer usage on a time basis. Furthermore, thegradient of the thick line is equivalent to the bit rate of the video,and indicates that data are input to the buffer at a constant rate. Areduction in the buffer usage at a constant interval indicates that thedata are decoded. Besides, the intersection of an oblique dotted lineand the time basis indicates a time that the data transfer of the videoframe to the video buffer is started.

Hereinafter, a complex image A in the video data will be described as anexample. Since an image A requires a large coding amount as shown inFIG. 39B, the data transfer to the video buffer should be started at atime t1 in the drawing in place of the decoding time of the image A. (Atime from the data input start time t1 till the decoding will bereferred to as vbv_delay). As a result, the AV data are multiplexed inthe position (time) of the video pack shown in an oblique line. On theother hand, the transfer of the audio data which does not requiredynamic coding amount control differently from the video data does notneed to be particularly made earlier than the decode time. For thisreason, generally, the multiplexing is carried out a little before thedecode time. Accordingly, the video data and the audio data which arereproduced at the same time are multiplexed in the state in which thevideo data are preceded. In the MPEG, a time that data can be stored inthe buffer is restricted, and all the data but still picture data aredefined such that they should be output from the buffer to the decoderwithin one second after they are input to the buffer. For this reason, ashift of the multiplexing of the video data and the audio data is onesecond at the maximum (strictly speaking, there is a further shift bythe reorder of the video data).

While the video has been followed by the audio in this example, theaudio can also be followed by the video in respect of theory. When asimple picture having a high compression ratio is prepared for the videodata and the audio data are transferred unnecessary quickly, such datacan be created intentionally. However, the precedence can be givenwithin one second at the maximum based on the restrictions of the MPEG.

(Description of Tape Media)

Next, description will be given to tape media.

FIG. 40 is a diagram illustrating a relation between a tape and a taperecorder (recording head). As shown in the figure, recording areas forvideo data and audio data are separately provided in parallel with atape running direction. Therefore it is easy to record audio dataindependently. In a conventional analog video tape recorder,reproduction and recording can be carried out simultaneously with onehead since a delay time from reproduction to recording is almost zero.

The DVD-RAM expected as the next generation AV recording media forexample has the following problems.

The biggest problem to an after-recording operation in the DVD recorderis caused by an MPEG stream which is AV data to be recorded by the DVDrecorder and the difference of mechanism between a video recorder andthe DVD recorder.

In the video recorder, as described in the prior art, each of video andaudio channels is independently recorded on a tape. The after-recordingoperation of an audio can easily be carried out because there is nodelay from playback to sound recording. In the DVD recorder, however, avideo and an audio are recorded in one multiplexed stream. One opticalpick-up is used for reading and writing operations. A time difference ismade from playback to recording, since one track buffer is provided forimplementing a variable bit rate. Even though two optical pick-ups areprovided, they should be operated independently. Even if each of theoptical pick-ups can be operated independently, the recording andplayback operations cannot be carried out at the same time in theDVD-RAM for changing a rotating speed for each zone when a region to beaccessed by each of the pick-ups is provided across different zones.

As described in the prior art, a time stamp for AV synchronous playbackis described on the MPEG stream. Therefore, in the case where a timestamp to be given to an audio stream to be recorded later isinconsistent with a time stamp given to an existing stream, a decoder isnot normally operated in some cases. For example, in the case where anSCR given to a video pack in the existing stream and an SCR given to anaudio pack recorded later have the same time, two data to be processedon the time of the SCR by the decoder are simultaneously present.Consequently, the decoder cannot be normally operated. Thus, there is aproblem in that the worst hang up is caused.

The DVD-RAM can store audio streams in various kinds of format. The DVDrecorder can not know whether the DVD recorder can apply an after-recordoperation to the DVD-RAM in which data has been recorded by otherrecorders. Therefore the stream must be analyzed at start of datarecording.

SUMMARY OF THE INVENTION

This invention is directed to provide information recording medium whichactualize easy determination of a possibility of after-recording on therecording medium. This invention is also directed to provide anapparatus and a method for recording data to such a recording medium.

In a first aspect of the invention, a recording medium comprises anaudio stream capable of being replaced with an after-recorded audiostream; and audio attribute information including bit rate informationindicative of a bit rate of the audio stream. In the recording medium, aplurality of audio streams may be stored therein. At least one of theplurality of audio streams may be the audio stream capable of beingreplaced with an after-recorded audio stream. The audio stream capableof being replaced with an after-recorded audio stream may be one audiostream which is provided for the other audio stream carrying originalaudio data and has same audio attribute as the other audio stream.

In a second aspect of the invention, an apparatus is provided forperforming after-recording to an audio stream recorded on the recordingmedium according to the invention. The apparatus comprises a checkingsection for checking a possibility of after-recording operation to therecorder before after-recording operation starts, and an operationsection for performing the after-recording operation.

In a third aspect of the invention, a method is provided for performingafter-recording to an audio stream recorded on the recording mediumaccording to the invention by using a recording apparatus. The methodcomprises referring to the bit rate information in the audio attributeinformation, determining whether or not the apparatus is able to encodethe audio stream to be after-recorded in a bit rate of the bit rateinformation, and deciding that the apparatus is able to performafter-recording when the apparatus is determined to be able to encodethe audio stream in the bit rate.

In accordance with the present invention, it is possible to determinewhether or not the after-recording operation to an audio stream can beperformed. Therefore, the recorder, for example, provides a warning to auser when the recorder does not have enough ability to process the audiostream for after-recording.

RELATED REFERENCE

It should be noted that this application is based on application No.11-38370 filed in Japan, the coritents of which is herein incorporatedby reference.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing the logical structure of a disc in thesecond embodiment.

FIG. 2 is a diagram showing a structure in an AV file for a motionpicture or movie data.

FIG. 3 is a diagram showing a structure in an AV file for a stillpicture.

FIG. 4 is a diagram showing a relationship between AV data andmanagement information.

FIG. 5 is a diagram showing the structure of RTR_VMG.

FIG. 6 is a diagram showing the structure of RTR_VMGI.

FIG. 7 is a diagram illustrating VERN and TM_ZONE formats.

FIG. 8 is a diagram showing the structure of PL_SRP.

FIG. 9 is a diagram illustrating PL_TY and PL_CREATE formats.

FIG. 10 is a diagram illustrating a PTM recording format.

FIG. 11 is a diagram illustrating an S_VOB_ENTN recording format.

FIG. 12 is a diagram showing the structure of M_AVFIT.

FIG. 13 is a diagram illustrating V_ATR and A_ATR formats.

FIG. 14 is a diagram illustrating SP_ATR and SP_PLT formats for a motionpicture.

FIG. 15 is a diagram showing the structure of M_AVFI.

FIG. 16 is a diagram showing the structure of M_VOBI.

FIG. 17 is a diagram illustrating a VOB_TY format.

FIG. 18 is a diagram showing the structure of TMAPI.

FIG. 19 is a diagram illustrating a VOBU_ENT format.

FIG. 20 is a diagram showing the structure of S_AVFIT.

FIG. 21 is a diagram illustrating V_ATR and OA_ATR formats.

FIG. 22 is a diagram illustrating SP_ATR and SP_PLT formats for a stillpicture.

FIG. 23 is a diagram showing the structure of S_AVFI.

FIG. 24 is a diagram showing the structure of S_VOB_ENT.

FIG. 25 is a diagram illustrating an S_VOB_ENT_TY format.

FIG. 26 is a diagram showing the structure of UD_PGCIT.

FIG. 27 is a diagram showing the structure of TXTDT_MG.

FIG. 28 is a diagram showing the structure of PGCI.

FIG. 29 is a diagram illustrating a PG_TY format.

FIG. 30 is a diagram showing the structure of CI.

FIG. 31 is a diagram illustrating a C_TY format.

FIG. 32 is a diagram showing the structure of C_EPI.

FIG. 33 is a diagram illustrating an EP_TY1 format.

FIG. 34 is a block diagram showing the drive device of a DVD recorder.

FIG. 35A is a diagram showing an address space on a disc, and FIG. 35Bis a chart showing a data storage amount in a track buffer.

FIG. 36 is a picture correlation diagram in an MPEG video stream.

FIG. 37 is a diagram showing the structure of an MPEG system stream.

FIG. 38 is a diagram showing the structure of an MPEG system decoder(P-STD).

FIG. 39A is a diagram showing video data, FIG. 39B is a chart showing avideo buffer usage, FIG. 39C is a diagram showing the MPEG systemstream, and FIG. 39D is a diagram showing audio data.

FIG. 40 is a diagram showing the structure of a recording band on atape.

FIG. 41A is a diagram illustrating the directory structure, and FIG. 41Bis a diagram illustrating physical allocation on the disc.

FIG. 42A is a diagram illustrating the management information, and FIG.42B is a diagram illustrating the structure of stream data.

FIG. 43 is a diagram illustrating the structure of MPEG stream includingband area for after-recording date.

FIG. 44 is a diagram illustrating a way of inserting after-recordingdata into the MPEG stream.

FIG. 45 is a diagram illustrating a partial after-recording.

FIG. 46 is a diagram illustrating a way of restoring after-recordedaudio stream.

FIG. 47 is a state transition diagram of an audio stream.

FIG. 48 is a block diagram of a DVD recorder in the first embodiment.

FIG. 49 is a block diagram of the encoder.

FIG. 50 is a block diagram of a DVD recorder with four track buffers.

FIG. 51 is a diagram illustrating an after-recording operation in theencoder.

FIG. 52A is a timing chart of track buffers, and FIG. 52B is a diagramshowing data area including data stored in track buffers.

FIG. 53 is a diagram illustrating the structure of a system controllerin the second embodiment.

FIG. 54 is a flowchart of process on after-recording or dubbing by a DVDrecorder in the second embodiment.

FIG. 55 is a flowchart of a check routine for checking possibility of anafter-recording operation in the after-recording process.

FIG. 56 is a flowchart of check routine for checking an attribute of anaudio stream in the after-recording possibility check routine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described in detail by using a DVDrecorder and a DVD-RAM according to an embodiment of the presentinvention.

First Embodiment

(Logical Structure on DVD-RAM)

First of all, the logical structure on the DVD-RAM will be describedwith reference to FIGS. 41A and 41B. FIG. 41A shows a data structure ona disc seen through a file system, and FIG. 41B shows a physical sectoraddress on a disc.

The head portion of the physical sector address has a lead-in regionwhich stores a reference signal necessary for stabilizing a servo, anidentification signal with other media and the like. A data region isprovided following the lead-in region. In this portion, logicallyeffective data are recorded. Finally, a lead-out region is provided andstores the same reference signal as in the lead-in region and the like.A management information for the file system which is referred to as avolume information is recorded on the head of the data region. Since thefile system is not directly related to the contents of the presentinvention, the description of it will be omitted.

Through the file system, the data in the disc can be dealt with as adirectory or a file as shown in FIG. 41A. All the data to be dealt withby the DVD recorder are put on a VIDEO_RT directory under a ROOTdirectory as shown in FIG. 41A. A file to be dealt with by the DVDrecorder is roughly classified into two kinds, that is, one managementinformation file and at least one AV file (ordinarily, a plurality offiles).

(Management Information File)

Next, the contents of the management information file will be describedwith reference to FIG. 42A.

The management information file is roughly divided into a VOB table anda PGC table. VOB (Video Object) means a program stream of MPEG. PGCdefines the playback order of Cell which uses any partial section (orall sections) in the VOB as one logical playback unit. In other words,the VOB is a unit which is significant as the MPEG, and the PGC is aunit at which a player plays back.

The VOB table stores the number of VOBs (Number_of_VOBs) and each VOBinformation therein. The VOB information comprises a corresponding AVfile name (AV_File_Name), a VOB identifier in the disc (VOB_ID), a startaddress in the AV file (VOB_Start_Address), an end address in the AVfile (VOB_End_Address), a playback time length of the VOB(VOB_Playback_Time) and an attribute information of the stream(VOB_Attribute).

A stream attribute information field comprises a video attribute(Video_Attribute), a first audio stream attribute (Audio0_Attribute) anda second audio stream attribute (Audio1_Attribute). The audio streamattribute information comprises an audio coding mode (Coding_Mode), anapplication flag (Application_Flag), a quantization coefficient(Quantization), a sampling frequency (Sampling_Frequency) and the numberof audio channels (Number_of_channels).

The PGC table includes the number of PGCs (Number_of_PGCs) and each PGCinformation therein. The PGC information comprises the number of Cells(Number_of_Cells) in the PGC and each Cell information. The cellinformation comprises corresponding VOB_ID, a playback start time in theVOB (Cell_Start_Time), a playback time in the VOB (Cell_Playback_Time),a playback start address in the VOB (Cell_Start_Address), a playback endaddress in the VOB (Cell_End_Address), an audio flag (Audio_Flag) forspecifying that audio signal played back in the Cell is an originalaudio or a after-recording audio. The cell information further comprisesCell_Start_Address and Cell_End_Address for the after-recording audio.

(AV File)

Next, an AV file will be described with reference to FIG. 42B.

The AV file includes at least one VOB (ordinarily, a plurality of VOBs).The VOB is continuously recorded in the AV file. The VOB in the AV fileis managed by the VOB information of the above-mentioned managementinformation file. A player can access the VOB by first accessing themanagement information file to read out the start and end addresses ofthe VOB. Moreover, the Cell is defined as a logical playback unit in theVOB. The Cell is the partial playback section (or the whole sections) ofthe VOB and can be freely set by a user. By the Cell, it is possible toedit AV data simply without actual operation of the AV data. In the samemanner as the VOB, an access information about the Cell is managed inthe Cell information in the management information file. The player canaccess the Cell by first accessing the management information file toread out the start and end addresses of the Cell.

The address information of the Cell is based on the VOB and the addressinformation of the VOB is based on the AV file. Therefore, the playeractually accesses the AV file by adding the address information of theVOB to the address information of the Cell to calculate an addressinformation in the AV file.

(Structure of VOB)

FIG. 43 is a diagram showing the structure of the VOB according to thepresent embodiment.

Two audio streams are set to an audio stream #1 and an audio stream #2,respectively. As shown in FIG. 43, the same audio stream is stored inthe audio stream #1 and the audio stream #2.

It is to be noted that the audio streams are not simply identical asstreams but are identical in pack and packet units. The value of SCRs(System Clock References) of a pack header, the value of stream numbersof a packet header and the value of original_or_copy are different.However, other fields, for example, PST and the like have the samevalues. Of course, the contents of a payload are identical.

The fields of original_or_copy are different in order to explicitlyindicate, in the streams, that the stream #1 is an original stream andthe stream #2 is a dummy stream for the after-recording operation. Theflags may have the same values.

By putting such two audio streams in the VOB, one of the original audiodata can remain even if one of the audio streams is recorded by theafter-recording operation as shown in FIG. 44.

For the following purpose, the two audio streams are put in. A recordingregion for the after-recording operation, that is, a recording band iskept. In addition, if the attribute of the audio stream to beafter-recorded, that is, a coding mode and a bit rate are set identicalto that of the audio stream recorded in a dummy, a pack and a packetheader become completely identical and the after-recording operation canbe carried out only by exchanging the contents of the payload.

This means that even though the system encoder of the MPEG should carryout the multiplexing operation of the audio pack so that an audio bufferneither underflows nor overflows, the multiplexing operation can beomitted on the after-recording operation.

When the after-recording operation is to be carried out in variouscoding modes and bit rates, the audio pack should be replaced not onlyto ensure a band but also to prevent the overflow and underflow of theaudio buffer. Therefore, it is impossible to simply ensure thereplacement of the audio pack between sets having different algorithms.

In the present embodiment, the SCR and the PTS are not changed in thesame coding mode and the same bit rate but data are rewritten in a packunit such that only the contents of the audio payload are replaced.

Of course, while the contents of the pack header and the packet headerincluding the SCR and the PTS may be rewritten, it is apparent that thecompleted stream should satisfy the conditions of the MPEG stream.

Next, the reason why the same audio data are to be recorded in thestream #1 and the stream #2 will be described with reference to FIG. 45.

For example, in the case where a part of the VOB is to beafter-recorded, when the data recorded as the stream #2 are silent orhave insignificant contents, for example, insignificant data andsignificant data are switched with each other on the boundary between aafter-recorded portion and a non-after-recorded portion.

Since the DVD recorder has only one audio decoder, the stream #1 and thestream #2 cannot be played back at the same time. Accordingly, when thepartial after-recording operation is to be carried out, it is necessaryto designate the audio stream to be played back to a decoder so as toswitch the audio stream from original data to after-recorded data orfrom after-recorded data to original data on the boundary portion. Theaudio stream to be played back is generally designated by control fromthe host side, that is, a microprocessor. Therefore, it is hard todesignate the switching in a frame unit.

By recording the same audio data as the original on the dummy audiostream itself as shown in FIG. 45, it is also possible to continuouslyplay back on the boundary portion where the partial after-recordingoperation is executed.

The above-mentioned problem of the partial after-recording operation canbe solved when the audio streams are not completely identical but havethe same contents, that is, are data having the same contents as analogdata during the playback. Description will be given to the reason whytwo completely identical streams are required to be recorded.

When the user wants to turn back the after-recorded audio data (that is,to erase the audio data) after the partial after-recording operation, itis necessary to record some data again because the overwritten datacannot be turned back. When the silent audio stream is to be recorded,the above-mentioned problem of the partial after-recording operation iscaused when the user tries the after-recording operation again in thepartial section of the silent audio stream section.

In the case where the two identical audio streams are used in the packand packet units except the SCR and the stream number as shown in FIG.46, an original state can be restored by copying data in the packet unitfrom the stream #1 to the stream #2. At this time, it is apparent thatthe stream number in the packet header should be modified.

(State of Audio Stream #2)

FIG. 47 is a diagram showing the state of the stream #2 recorded for theafter-recording operation described above. The state of the stream #2 isdivided into “same audio stream”, “stream having the same audiocontents”, “after-recorded stream” and “individual stream”. As describedabove, it is possible to carry out the after-recording operation fromthe same audio stream and the stream having the same audio contents. Onthe contrary, it is possible to return only to the same audio stream.That is, it is possible to return from the after-recorded audio streamto the same stream.

Moreover, the after-recorded stream can be regarded as an independentstream. In the independent stream (for example, the audio stream #2 inwhich silent data are recorded), the after-recording operation can becarried out for the whole VOB. However, the partial after-recordingoperation of the VOB causes the above-mentioned problem.

The above-mentioned state is managed in an Application Flag on theDVD-RAM disc.

(Structure of DVD Recorder)

Next, the structure of the DVD recorder will be described with referenceto FIG. 48.

In the drawing, the DVD recorder comprises a user interface 7801, asystem controller 7802, an input section 7803, an encoder 7804, anoutput section 7805, a decoder 7806, a track buffer 7807 and a drive7808. The user interface 7801 transfers data displayed to the user oraccepts a request from the user. The system controller 7802 serves towholly perform management and control. The input section 7803 includingan AD converter inputs video and audio data. The output section 7805outputs a video and audio data. The decoder 7806 decodes an MPEG stream.

(Recording Operation of DVD Recorder)

The recording operation of the DVD recorder will be described.

The user interface 7801 first accepts a request from the user. The userinterface 7801 transmits the request from the user to the systemcontroller 7802. The system controller 7802 interprets the request fromthe user and gives a process request to each module. When the user givesa request for picture recording, the system controller 7802 gives arequest for encoding to the encoder 7804.

The encoder 7804 carries out video encoding, audio encoding and systemencoding for video and audio information sent from the input section7803, and transfers the encoded data to the track buffer 7807.

Next, the system controller 7802 gives, to the driver 7808, a requestfor writing data stored in the track buffer, and the drive 7808 fetchesdata from the track buffer and records the fetched data in the DVD-RAM.

The user's request for stop is transmitted to the system controller 7802through the user interface 7801. The system controller 7802 gives arequest for encoding stop to the encoder 7804, and the encoder 7804stops an encoding process when the data are completely encoded andinforms the system controller 7802 of encoding termination.

Then, the system controller 7802 gives a request for a writingtermination to the drive 7808, and the drive 7808 stops reading andwriting data to the DVD-RAM when the track buffer 7807 becomes empty.

Finally, the system controller 7802 modifies an AV file information, aclip sequence information and a file system information for the recordedVOB, and records them in the DVD-RAM through the drive 7808. Inparticular, a value of Application Flag is recorded as the same audiostream.

For the recording operation, it is important that two audio streams areinserted into the outputting VOB in the encoder 7804, while one audiodata is input.

A process of inserting the two audio streams will be described withreference to FIG. 49. FIG. 49 is a diagram showing the structure of theencoder. As shown, the encoder comprises a video encoder 7804 a, anaudio encoder 7804 b and a system multiplexer 7804 c.

The video encoder 7804 a encodes an input video signal into an MPEGvideo stream. The audio encoder 7804 b encodes an input audio signalinto an audio stream. At this time, there is one audio stream. Next, themultiplexer 7804 c performs packing, packetizing and multiplexing thevideo stream and audio stream. In the multiplexing process, copy iscarried out in an audio pack unit and the multiplexing is executed forthe two audio streams.

The audio stream may be copied in a form of a packet, or in a form of apayload immediately before the packetizing process. As described above,the two audio streams are inserted into the VOB.

(After-recording Operation of the DVD Recorder)

Next, description will be given to the after-recording operation in theDVD recorder.

First of all, description will be given to the input and output of AVdata on the after-recording operation by the DVD recorder. In the inputand output of the AV data, data are read or written in a unit called anAV block.

The AV block indicates the continuous recording region shown in FIG. 35.When the continuous recording region is much greater than a continuousrecording length necessary for seeking the continuous recording region,it may be divided into small regions as AV blocks.

Subsequently, the track buffer 7807 is divided into track buffer1 andtrack buffer3 to be used for playback and track buffer2 and trackbuffer4 to be used for recording. This state is illustrated in FIG. 50.

The input and output of the track buffer will be described in a timeseries with reference to FIG. 52.

Description will be given by taking, as an example, the case where theVOB is constituted by four AV blocks A, B, C and D as shown in FIG. 52B.

FIG. 52A is a diagram representing the buffer storage amounts of thetrack buffers 1, 2, 3 and 4 on a time base. At the track buffer1 (TB1)and the track buffer3 (TB3), the data storage amount is increasedbecause data are input from the drive, that is, data are read out forplayback from the DVD-RAM, and the data storage amount is decreasedbecause data are supplied to the decoder.

On the contrary, at the track buffer2 (TB2) and the track buffer4 (TB4),the data storage amount is increased because data are input from theencoder after the after-recording operation, that is, data are recorded(overwritten) on the DVD-RAM, and the data storage amount is decreasedbecause data are supplied to the drive for recording in the DVD-RAM.

During period T1 in the drawing, first, the AV block A is read out onthe track buffer1 and the after-recording operation starts immediatelyafter the data are read out. During period Ta, the after-recordingoperation is carried out for the AV block A. The after-recorded data ofthe AV block A are recorded on TB2. Therefore, the storage amount of theTB2 is increased during the period Ta.

The drive reads the next AV block B immediately after the period T1. TheAV block A and the AV block B are not present on the same continuousrecording region, and therefore the AV block B is read out after theseeking of a head (period T2).

After the after-recording operation of the AV block A is ended, theafter-recording operation of the AV block B then starts (period Tb). Thedata of the AV block B stored in the track buffer3 are supplied to thedecoder. The data after-recorded through the encoder are stored in thetrack buffer4 during the period Tb.

Immediately after the after-recording operation of the AV block A isended, the drive overwrites the after-recorded data of the AV block Astored in the track buffer2 onto the AV block A (period T3).

When the overwriting process on the AV block A is completed, the drivethen reads out the AV block C. The read data on the AV block C arestored in the track buffer1 (period T4).

By repeating the above-mentioned operation, the after-recording processcan be carried out.

Next, description will be given to a process flow in the DVD recorder.

The user's request for the after-recording operation is transmitted tothe system controller 7802 through the user interface 7801. First ofall, the system controller 7802 gives, to the drive 7808, a request forreading out the VOB to be after-recorded.

The drive 7808 reads out the VOB to be after-recorded from the DVD-RAMin an AV block unit and records the read VOB in the track buffer1.

At the same time, the system controller 7802 gives a request for theafter-recording process to the encoder 7804.

The encoder 7804 performs the audio-encoding of audio data input fromthe input section 7803, reads out an audio pack including the audiostream #2 in the stream sent from the decoder, replaces a payload withthe encoded after-recording audio stream, and records theafter-recording audio stream in the track buffer2. This state is shownin FIG. 51.

When the after-recording process of the AV data stored in the trackbuffer1 is completed, the encoder 7804 consecutively starts theafter-recording process of the AV data recorded in the track buffer3 andnotifies the system controller 7802 that the after-recording process ofthe track buffer1 is ended.

Next, the system controller 7802 gives, to the drive 7808, a request forwriting the data of the track buffer 2.

The drive 7808 overwrites and records the data of the track buffer 2 onthe DVD-RAM after the completion of writing into the track buffer3.

By sequentially carrying out the above-mentioned processes for the trackbuffer1, the track buffer2, the track buffer3 and the track buffer4 asdescribed above, the after-recording operation can be executed.

Moreover, when the VOB is completely read out from the DVD-RAM, thedrive 7808 informs the system controller 7802 of termination of the VOBreading process.

The system controller 7802 gives a request for termination ofafter-recording to the encoder 7804. The encoder 7804 carries out theafter-recording process until the after-recording processes of all theaudio data remaining in the track buffer1 and the track buffer3 areterminated. The encoder 7804 informs the system controller 7802 of theafter-recording termination when the after recording processes of allthe data are-completed.

Next, the system controller 7802 gives a request for a writing endprocess to the drive 7808. The drive 7808 overwrites and records all theVOB data remaining in the track buffer2 and the track buffer4 on theDVD-RAM disc and informs the system controller 7802 that theafter-recording process is completed after the completion of therecording operation.

The system controller 7802 changes the Application Flag to the“after-recorded” and carries out the recording operation on the DVD-RAMthrough the drive 7808 again.

(Playback (Reproduction) Operation of DVD Recorder)

Next, the playback operation of the DVD recorder will be described.

The user's request for a playback process is transmitted to the systemcontroller 7802 through the user interface 7801. The system controller7802 gives a request for reading the VOB to the drive 7808, and thedrive 7808 reads out the VOB data from the DVD-RAM and transfers the VOBdata to the track buffer 7807.

Then, the system controller 7802 gives a request for playing back theVOB to the decoder 7806, and the decoder 7806 reads out data from thetrack buffer 7807, decodes the read data and outputs the decoded datathrough the output section 7805.

When the VOB is completely read out, the drive 7808 informs the systemcontroller 7802 of termination of the reading process, and the systemcontroller 7802 gives a request for ending the playback to the decoder7806. The decoder 7806 carries out the reading and decoding operationsof the data until the data of the track buffer 7807 becomes empty, andinforms the system controller 7802 of the end of the playback operationafter the completion of decoding process for all data.

At this time, the following is important. In the case where the usergives a request for switching the audio stream, that is, a request forplaying back the audio stream #2, the system controller 7802 informs theuser through the user interface 7801 that the switching is impossible,without playing back the audio stream #2 when the value of theApplication Flag indicates the same audio streams or the same audiocontents.

When the same audio streams or the same audio contents are recorded inthe audio stream #2, an error message is displayed for the user. Thisprevents the user from thinking that the switching has failed or thatthe DVD recorder is out of order, because the user performing theswitching operation of the audio stream expects the playback of an audiostream different from the audio stream #1, however just the same audiois played back in this case even if audio stream to be played back isswitched to the audio stream #2.

While the audio stream 2 has been a dummy audio stream for theafter-recording operation in the present embodiment, the audio stream 1may be the dummy audio stream for the after-recording operation.

The payloads in the packets between the two audio streams have beencoincident with each other in the present embodiment. The sizes of theaudio data to be packetized may be different from each other, and may beidentical to the audio streams recorded in the completed VOB or have thesame contents as the audio streams recorded in the completed VOB.

In the present embodiment, furthermore, restrictions may be put on thatthe audio pack of the audio stream #1 always comes earlier between thecorresponding audio packets between the two audio streams or the audiopack of the audio stream #2 may be arranged immediately after the audiopack of the audio stream #1. By putting such restrictions, it is easy tofind the audio pack of the audio stream #2 during the after-recordingoperation. Moreover, restrictions can be put on that the audio stream #2precedes the audio stream #1.

Moreover, there have been four kinds of values of the Application Flag,that is, “the same audio stream”, “the stream having same audiocontents”, “the after-recorded stream” and “the individual stream”. The“same audio stream” and the “same audio contents” may be dealt with asone state, the “after-recorded stream” and the “individual stream” maybe dealt with as one state. Also the “same audio stream”, “stream havingsame audio contents” and “after-recorded stream” may be dealt with asone state.

Furthermore, although four track buffers have been provided in thedescription of the after-recording operation, the AV data may beoverwritten on the track buffers by sharing the track buffer1 and trackbuffer2, and by sharing the track buffer3 and track buffer4,respectively.

Second Embodiment

It has been possible to implement the after-recording operation which ishard to perform in the DVD and the DVD recorder in the first embodiment.However, the DVD and the DVD recorder further have the followingproblem.

Different from the conventional tape media, the DVD can carry outrecording in various audio stream formats. This causes theafter-recording operation in the DVD recorder to be hard to perform.

Concretely, the audio stream which can be recorded in the DVD has threekinds of formats of AC-3, MPEG audio and linear PCM. Moreover, there arevarious modes such as recording channel numbers, a recording bit rateand the like in individual formats.

On the other hand, a general audio encoder rarely can operate with allencode modes, channel numbers and bit rates, and can operate with only amode suitable for each merchandise target. In other words, when theafter-recording operation is applied to the disc on which data have beenrecorded by the other DVD recorder, the after-recording operation shouldbe actually started or the recorded audio stream should be analyzed inorder to decide whether the after-recording operation is operable ornot.

The DVD and DVD recorder in this embodiment have basically the samestructure as in the first embodiment, and are characterized by a methodof having a management information on the disc and the operation of arecorder for performing the after-recording process. In the presentembodiment, the difference from the first embodiment will be mainlydescribed.

(Logical Structure of DVD-RAM)

First of all, the logical structure of the DVD-RAM will be describedwith reference to FIG. 1. FIG. 1 shows a physical sector address on adisk and a data structure on the disk which can be seen through a filesystem.

All the data to be dealt with by the DVD recorder are put on a DVD_RTRdirectory immediately under a ROOT directory as shown in FIG. 1. Thefile to be dealt with by the DVD recorder is roughly divided-into 2kinds of files, that is, one management information file and at leastone AV file (ordinary a plurality of AV files). The AV file stores anRTR_MOV.VRO file for storing a motion picture and an RTR_STO.VRO filefor storing a still picture and audio data which are recorded at thesame time with the motion picture or the still picture.

FIG. 2 is a diagram showing the structure of the RTR_MOV.VRO file havingmotion picture. As shown in FIG. 2, M_VOB (Movie Video Object) which isthe program stream of MPEG is provided in the RTR_MOV.VRO file in orderof picture recording.

The M_VOB comprises a VOBU (Video Object Unit) in which one unit is 0.4to 1.0 second based on a video reproducing time. The VOBU comprisesV_PCK (Video Pack), A_PCK (Audio Pack) and SP_PCK (Sub-picture Pack).Each pack is constituted in a 2 KB unit.

Video data in the VOBU also comprises at least one GOP (Group ofPictures). The GOP is the decode unit of the MPEG video and includes aplurality of P pictures and B pictures with the I pictures in a head.

FIG. 3 is a diagram showing the structure of the RTR_STO.VRO file inwhich a still picture and audio data are recorded. As shown in FIG. 3,S_VOB (Still Picture Video Object) which is an MPEG program stream forthe still picture is recorded in the RTR_STO.VRO file in order ofpicture recording.

A great difference between the M_VOB and the S_VOB is that motionpicture data and audio data are not mutually multiplexed but audio data(Audio part) are successively recorded after the still picture data(Video part), in addition to the recording of the still picture data inplace of the motion picture data. Moreover, the S_VOB is constituted byone VOBU. The VOBU comprises the V_PCK, the A_PCK and the SP_PCK.

(AV Data and Management Information)

Next, description will be given to the relationship between the M_VOBand S_VOB described above with reference to FIG. 4 and managementinformation.

As described above, AV data have two kinds of data, that is, the M_VOBfor a motion picture and S_VOB for a still picture. Each M_VOB hasmanagement information M_VOBI. Attribute information of thecorresponding M_VOB is recorded in M_VOBI. In case of the S_VOB, whenmanagement is carried out for each S_VOB, the amount of the managementinformation gets increased. Therefore, management information S_VOGI isprovided for each group S_VOG having a lump of S_VOBs. S_VOGI stores theattribute information of a corresponding S_VOB group.

It is important that the data of the MPEG stream have no linearitybetween a time and a data amount. As described above, a compressingmethod using a time correlation characteristic and compression using avariable length coding method which is referred to as VBR are executedin order to implement highly efficient compression in the MPEG stream.Therefore, the time and the data amount, that is, address information donot uniquely correspond to each other.

The M_VOBI has a filter (TMAP) for converting a time and an address. TheS_VOGI has a filter (S_VOB Entries) for converting still picture numberand an address in the group.

Next, description will be given to the management information of aplayback sequence.

The playback sequence is defined as a sequence (PGC) of a cellindicative of a partial or whole interval of the M_VOB and the S_VOG.The playback sequence has two kinds of parts, that is, an original PGCand a user-defined PGC. The original PGC refers to all the AV data inthe disc. The user-defined PGC defines a playback order of AV data whichthe user selects in the disc (plural definitions can be obtained). Theoriginal PGC is also called a program set (Program Set), and includes alayer which is called a program (Program) having a plurality of cellslogically bundled therebetween. The user-defined PGC is also called aplay list (Play List) and includes no Program therebetween differentlyfrom the original PGC.

(Management Information File)

Next, the contents of the management information file “RTR. IFO” will bedescribed with reference to FIGS. 5 to 33.

“RTR_VMG” (FIG. 5)

Management information referred to as RTR_VMG (Real Time Recording VideoManagement) is recorded in the RTR. IFO file. The RTR_VMG comprisesseven tables of RTR_VMGI, M_AVFIT, S_AVFIT, ORG_PGCI, UD_PGCIT, TXTDT_MGand MNFIT.

Next, each table will be described in detail.

“RTR_VMGI” (FIG. 6)

RTR_VMGI (Real Time Recording Video Management Information) comprisesVMGI_MAT and PL_SRPT.

“VMGI_MAT” (FIG. 6)

VMGI_MT (Video Management Information Management Table) stores thefollowing information as information related to the whole disc. A playerand a recorder can first read the VMGI_MAT to roughly obtain structuralinformation of the disc.

VMG_ID (Video Management Identifier)

VMG_ID stores an identifier “DVD_RTR_VMG0” indicating that videorecording data are recorded in this disc.

RTR_VMG_EA (RTR_VMG End Address)

The end address of the RTR_VMG is recorded therein.

VMGI_EA (VMGI End Address)

The end address of the VMGI is recorded therein.

VERN (Version Number)

The version number of a recording format of the video recording data isrecorded in accordance with a format shown in FIG. 7.

TM_ZONE (Time Zone)

Recorded therein is a time zone to be used by all date and timeinformation recorded in this disc. As shown in FIG. 7, TM_ZONE comprisesTZ_TY (time zone type) and TZ_OFFSET (time zone offset). TZ_TY indicateswhich one of the Greenwich mean time as a universal time and a standardtime for each region is used for the reference of date information.TZ_OFFSET records a time difference between the date and the Greenwichmean time.

STILL_TM (Still Time)

A static time length obtained when displaying a soundless still pictureis recorded.

CHRS (Character Set Code for Primary Text)

A character set code for a primary text which will be described below isrecorded therein.

M_AVFIT_SA (M_AVFIT Start Address)

Start address of M_AVFIT is recorded therein. When M_AVFIT is accessed,a seek is carried out up to this start address.

S_AVFIT_SA (S_AVFIT Start Address)

Start address of S_AVFIT is recorded therein. When S_AVFIT is accessed,a seek is carried out up to this start address.

ORG_PGCI_SA (ORG_PGCI Start Address)

Start address of ORG_PGCI is recorded therein. When ORG_PGCI isaccessed, a seek is carried out up to this start address.

UD_PGCIT_SA (UD_PGCIT Start Address)

Start address of UD_PGCIT is recorded therein. When UD_PGCIT isaccessed, a seek is carried out up to this start address.

TXTDT_MG_SA (TXTDT_MG Start Address)

Start address of TXTDT_MG is recorded therein. When TXTDT_MG isaccessed, a seek is carried out up to this start address.

MNFIT_SA (MNFIT Start Address)

Start address of MNFIT is recorded therein. When MNFIT is accessed, aseek is carried out up to this start address.

“PL_SRPT” (FIG. 8)

PL_SRPT (Play List Search Pointer Table) is a table comprising PL_SRPTIand n PL_SRPs.

“PL_SRPTI” (FIG. 8)

PL_SRPTI (Play List Search Pointer Table Information) stores thefollowing information for accessing to PL_SRP.

PL_SRP_Ns (Number of PL_SRP)

Number of PL_SRPs is recorded therein.

PL_SRPT_EA (PL_SRPT End Address)

End address of PL_SRPT is recorded therein.

“PL_SRP” (FIG. 8)

Moreover, the following information for giving access to theuser-defined PGC which is actual data of the play list is recorded inPL_SRP (Play List Search Pointer).

PL_TY (Play List Type)

Any of the following values is recorded as a value for identifying thetype of a play list in accordance with a description format shown inFIG. 9.

0000b: only motion pictures

0001b: only still pictures

0010b: hybrid of motion pictures and still pictures

PGCN (PGC Number)

PGC number corresponding to the play list is recorded therein.. The PGCnumber indicates the recording order of PGC information in UD_PGCITwhich will be described below.

PL_CREATE_TM (Play List Recording Date)

Information about the date and time at which the play list was createdis recorded therein in accordance with the description format shown inFIG. 9.

PRM_TXTI (Primary Text Information)

Text information indicative of the contents of the play list is recordedtherein. For example, in the case where a television program is picturerecorded, the name of the program is recorded. Moreover, the primarytext information is constituted by a field for the ASCII code and afield of a character code set specified by the above-mentioned CHRS.

IT_TXT_SRPN (IT_TXT_SRP Number)

When information indicative of the contents of the play list areoptionally recorded as IT_TXT in addition to the above-mentioned primarytext, the IT_TXT_SRP number is recorded as link information to theIT_TXT to be recorded in the TXTDT_MG. The IT_TXT_SRP number indicatesthe recording order in TXTDT_MG which will be described below.

THM_PTRI (Thumb Nail Pointer Information)

Thumb nail information which is representative of the play list isdescribed.

“THM_PTRI” (FIG. 8)

In THM_PTRI is recorded the following information indicative of theposition of a thumb nail.

CN (Cell Number)

Cell number of a cell including a thumb nail is recorded therein. Thecell number indicates the recording order of cell information in theUD_PGCI to which the play list corresponds.

THM_PT (Thumb Nail Point)

When a cell indicated by the above-mentioned CN is a motion picturecell, the display time of a video frame to be used as a thumb nail isrecorded in accordance with a PTM description format shown in FIG. 10.The PTM is given in accordance with the reference time of a time stampdescribed in the MPEG program stream.

Moreover, when the cell indicated by the above-mentioned CN is a stillpicture cell, the still picture VOB entry number of a still picture tobe used as the thumb nail is recorded in accordance with an S_VOB_ENTNdescription format shown in FIG. 11. The still picture. VOB entry numberindicates the recording order of the still picture VOB entry in a stillpicture VOB group indicated by this cell.

“M_AVFIT” (FIG. 12)

M_AVFIT (Motion picture AV File Information Table) stores managementinformation corresponding to motion picture AV file “RTR_MOV.VRO” andcomprises M_AVFITI, M_VOB_STI and M_AVFI.

“M_AVFITI” (FIG. 12)

M_AVFITI (Motion picture AV File Information Table Information) storesthe following information necessary for giving access to M_VOB_STI andM_AVFI.

M_AVFI_Ns (Number of Motion Picture AV File Information)

Number of fields of succeeding AVFI information is indicated therein.When the value is “0”, there exists no AVFI, while when the value is“1”, there exists AVFI. Moreover, the presence of the AVFI alsocorresponds to that of RTR_MOV.VRO which is the AV file for motionpictures.

M_VOB_STI_Ns (Number of M_VOB_STI)

Number of fields of succeeding M_VOB_STI is indicated therein.

M_AVFIT_EA (M_AVFIT End Address)

The end address of M_AVFIT is recorded therein.

“M_VOB_STI” (FIG. 12)

M_VOB_STI (Movie VOB Stream Information) stores the followinginformation as the stream information of movie VOB.

V_ATR (Video Attribute)

The following video attribute information is recorded in accordance witha format shown in FIG. 13.

Video Compression Mode

Any one of the following values for identifying a video compression modeis recorded therein.

00b: MPEG-1

01b: MPEG-2

TV System

Any one of the following values for identifying a television system isrecorded therein.

00b: 525/60 (NTSC)

01b: 625 50 (PAL)

Aspect Ratio

Any one of the following values for identifying a resolution ratio isrecorded therein.

00b: 4×3

01b: 16×9

line21_switch_1

Recorded therein is any one of the following values for identifying thatclosed caption data for a field 1 are recorded or not in a video stream.

1b: Recorded

0b: Not recorded

line21_switch_2

Recorded therein is any one of the following values for identifying thatclosed caption data for a field 2 are recorded or not in the videostream.

1b: Recorded

0b: Not recorded

Video Resolution

Any one of the following values for identifying a video resolution isrecorded therein.

000b: 720×480 (NTSC), 720×576 (PAL)

001b: 702×480 (NTSC), 702×576 (PAL)

010b: 352×480 (NTSC), 352×576 (PAL)

011b: 352×240 (NTSC), 352×288 (PAL)

100b: 544×480 (NTSC), 544×576 (PAL)

101b: 480×480 (NTSC), 480×576 (PAL)

AST_Ns (Number of Audio Streams)

Number of audio streams recorded in corresponding VOB is recordedtherein.

SPST_Ns (Number of Sub-picture Streams)

Number of sub-picture streams recorded in corresponding VOB is recordedtherein.

A_ATR0 (Attribute of Audio Stream 0)

The following audio attribute information corresponding to an audiostream 0 (corresponding to the audio stream #1 described above) isrecorded in accordance with a format shown in FIG. 13.

Audio Coding Mode

Any one of the following values for identifying an audio compressingmethod is recorded.

000b: Dolby AC-3

001b: MPEG audio having no extended stream

010b: MPEG audio having an extended stream

011b: linear PCM

Application Flag

Any one of the following values for identifying application informationis recorded therein.

00b: No application

01b: Mixed audio channel number

10b: With auxiliary voice

Quantization/DRC

When using the MPEG audio, any one of the following values foridentifying the presence of DRC (Dynamic Range Control) information isrecorded therein.

00b: DRC data are not included in the MPEG stream.

01b: DRC data are included in the MPEG stream.

When using the LPCM audio, the following value for identifying theQuantization is recorded therein.

00b: 16 bits

fs

The following value for identifying a sampling frequency is recordedtherein.

00b: 48 kHz

Number of Audio Channels

Any one of the following values for identifying the number of audiochannels is recorded therein.

0000b: one channel (monophonic)

0001b: two channels (stereo)

0010b: three channels

0011b: four channels

0100b: five channels

0101b: six channels

0110b: seven channels

0111b: eight channels

1001b: two channels (dual monophonic)

Bitrate

Any one of the following values for identifying a bit rate is recordedtherein.

0000 0001b: 64 kbps

0000 0010b: 89 kbps

0000 0011b: 96 kbps

0000 0100b: 112 kbps

0000 0101b: 128 kbps

0000 0110b: 160 kbps

0000 0111b: 192 kbps

0000 1000b: 224 kbps

0000 1001b: 256 kbps

0000 1010b: 320 kbps

0000 1011b: 384 kbps

0000 1100b: 448 kbps

0000 1101b: 768 kbps

0000 1110b 1536 kbps

It is important that only the bit rate of a basic stream excluding anextended stream is recorded when the corresponding audio stream is theMPEG audio stream having the extended stream. The reason is that theextended stream cannot be expressed by the above-mentioned fixed bitrate because it carries out the compression using the variable lengthcoding method.

A_ATR1 (Attribute of Audio Stream 1)

The following audio attribute information corresponding to an audiostream 1 (corresponding to the above described audio stream #2 providedfor after-recording) is recorded in accordance with a format shown inFIG. 13. Individual fields are the same as the above-mentioned A_ATR0.

SP_ATR (Sub-picture Attribute)

The following sub-picture attribute information is recorded inaccordance with a format as shown in FIG. 14.

Application Flag

Any one of the following values for identifying application informationis recorded therein.

00b: No application

01b: Subtitles

10b: Animation

SP_PLT (Sub-picture Color Palette)

Color palette information for a sub-picture is recorded in accordancewith the format shown in FIG. 14.

“M_AVFI” (FIG. 15)

M_AVFI (Motion picture AV File Information) comprises informationnecessary for giving access to movie VOB (M_VOB), M_AVFI_GI, M_VOBI_SRPand M_VOBI.

“M_AVFI_GI” (FIG. 15)

M_VOBI_SRP_Ns is recorded in M_AVFI_GI (Motion picture AV FileInformation General Information).

M_VOBI_SRP_Ns (Number of Movie VOB Information Search Pointer)

Number of M_VOBI_SRP is recorded therein.

“M_VOBI SRP” (FIG. 15)

M_VOBI_SRP (Movie VOB Information Search Pointer) stores addressinformation for accessing each M_VOBI.

M_VOBI_SA (Movie VOB Information Start Address)

The start address of M_VOBI is recorded therein. The indicated addressherein can be used in seeking operation for accessing the VOBinformation.

“M_VOBI” (FIG. 16)

M_VOBI (Movie VOB Information) comprises management information of movieVOB, M_VOB_GI, SMLI, AGAPI, TMAPI and CP_MNGI.

“M_VOB GI” (FIG. 16)

M_VOB_GI (Movie VOB General Information) stores the followinginformation as the general information of the Movie_VOB.

VOB_TY (VOB_Type)

The attribute information of VOB is recorded therein in accordance witha format shown in FIG. 17.

TE

Any one of the following values for identifying the status of the VOB isrecorded therein.

0b: Normal status

1b: Temporary erasing status

A0_STATUS

Any one of the following values for identifying the status of an audiostream 0 is recorded therein.

00b: Original status

01b: Rewritten status

A1_STATUS

Any one of the following values for identifying the status of an audiostream 1 is recorded therein.

00b: Original status

01b: Rewritten status

10b: Dummy status for after-recording

11b: After-recorded status

APS

Any one of the following values for identifing analog copy preventingsignal control information is recorded the rein.

00b: NO APS

01b: Type 1

10b: Type 2

11b: Type 3

SML_FLG

Any one of the following values for identifying whether or not the VOBis seamlessly reproduced together with the VOB present just before.

0b: Seamless reproduction is impossible.

1b: Seamless reproduction is possible.

A0_GAP_LOC

Recorded therein is any one of the following values indicative of thepresence of an audio reproducing gap in the audio stream 0 and VOBUhaving an audio reproducing gap interval multiplexed.

00b: No audio reproducing gap

01b: Audio reproducing gaps are multiplexed to a head VOBU.

10b: Audio reproducing gaps are multiplexed to a second VOBU.

11b: Audio reproducing gaps are multiplexed to a third VOBU.

A1_GAP_LOC

Recorded therein is any one of the following values indicative of thepresence of an audio reproducing gap in the audio stream 1 and VOBUhaving an audio reproducing gap interval multiplexed.

00b: No audio reproducing gap

01b: Audio reproducing gaps are multiplexed to a head VOBU.

10b: Audio reproducing gaps are multiplexed to a second VOBU.

11b: Audio reproducing gaps are multiplexed to a third VOBU.

VOB_REC_TM (VOB Recording Date and Time)

The date and time on which the VOB was recorded is recorded therein inthe same format as in the PL_CREATE_TM shown in FIG. 9. It is importantthat the recording date and time indicates the recording date and timeof the display video frame of the VOB head and the VOB_REC_TM shouldalso be corrected when the VOB head video frame is changed by edit orpartial erasure. When the recording date and time is to be displayedsynchronously with the reproduction of the VOB as often seen in acamcoder, the recording date and time is possible to obtain by adding anelapsed time in the VOB to the VOB_REC_TM.

VOB_REC_TM_SUB (VOB Recording Date and Time Difference Information)

VOB_REC_TM_SUB is a field for absorbing the error of the VOB_REC_TM tobe modified when the VOB head video frame is changed by the edit and thepartial erasure on the VOB. The VOB_REC_TM has only information aboutyear, month, day, hour, minute and second as shown in FIG. 9. Therefore,in the case where the edit or erasure is carried out in each frame orfield, the VOB_REC_TM cannot provide a sufficient recording precision.By using this field, therefore, a fraction is recorded.

M_VOB_STIN (M_VOB_STI Number)

M_VOB_STI number corresponding to the VOB is recorded therein. M_VOB_STInumber shown herein is the recording order in the above-mentionedM_VOB_STI table.

VOB_V_S_PTM (VOB Video Start PTM)

The display start time of the VOB is recorded therein with the samereference time as a time stamp in a stream.

VOB_V_E_PTM (VOB Video End PTM)

The display end time of the VOB is recorded therein with the samereference time as a time stamp in a stream. It should be noted that thetime stamp in the stream indicates the display start time of the frame,while VOB_V_E_PTM stores the display end time, that is, a time obtainedby adding the display period of the frame to the display start time.

“SMLI” (FIG. 16)

SMLI (Seamless Information) stores the following information necessaryfor seamless reproduction with the last VOB. Moreover, this field isprovided only when “1b” is recorded in the above-mentioned SML_FLG.

VOB_FIRST_SCR (VOB Head SCR)

SCR in the first pack of the VOB is recorded.

PREV_VOB_LAST SCR (Previous VOB Last SCR)

SCR of the last pack of the previous VOB is recorded therein.

“AGAPI” (FIG. 16)

AGAPI (Audio Gap Information) stores the following information necessaryfor processing an audio reproducing gap in a decoder. Moreover, thisfield is provided in the case where a value other than “00b” is recordedin either the above-mentioned A0_GAP_LOC or A1_GAP_LOC.

VOB_A_STP_PTM (VOB Audio Stop PTM)

The time of the audio reproducing gap, that is, the time that thedecoder temporarily stops audio reproduction is recorded therein withthe same reference time as a time stamp in a stream.

VOB_A_GAP_LEN (VOB Audio Gap Length)

The time length of an audio reproducing gap is recorded with a precisionof 90 kHz.

“CP_MNGI” (FIG. 16)

CP_MNGI (Copy Management Information) comprises copy managementinformation for the VOB, CPG_STATUS and CPGI.

CPG_STATUS (Copy Protecting Status)

As the copy protecting status of the VOB, values for identifying “copyfree” or “one generation copying” are recorded therein.

CPGI (Copy Protecting Information)

Copy protecting information applied to the VOB is recorded therein.

“TMAPI” (FIG. 18)

TMPAI (Time Map Information) comprises TMAP_GI, TM_ENT and VOBU_ENT.

“TMAP_GI” (FIG. 18)

TMAP_GI (TMAP General Information) comprises TM_ENT_Ns, VOBU_ENT_Ns,TM_OFS and ADR_OFS. Each field is as follows.

TM_ENT_Ns (Number of TM_ENT)

Number of fields of TM_ENT which will be described below is recordedtherein.

VOBU_ENT_Ns (Number of VOBU_ENT)

Number of fields of VOBU_ENT which will be described below is recordedtherein.

TM_OFS (Time Offset)

The offset value of a time map is recorded therein with a video fieldprecision.

ADR_OFS (Address Offset)

An offset value in the AV file of the head of the VOB is recordedtherein.

“TM_ENT” (FIG. 18)

TM_ENT (Time Entry) comprises the following fields as access pointinformation for each constant interval TMU. TMU for NTSC is 600 videofields (NTSC), while TMU for PAL is 500 video fields.

VOBU_ENTN (VOBU_ENT Number)

The entry number of VOBU including a time indicated by the TM_ENT(TMU×(N−1)+TM_OFS for Nth TM_ENT) is recorded therein.

TM_DIFF (Time Difference)

A difference between a time indicated by the TM_ENT and the displaystart time of VOBU indicated by the above-mentioned VOBU_ENTN isrecorded therein.

VOBU_ADR (VOBU Address)

A head address in the VOB of the VOBU indicated by the abovementionedVOBU_ENTN is recorded therein.

“VOBU_ENT” (FIG. 19)

VOBU_ENT (VOBU Entry) stores the following structure information of thecorresponding VOBU in a format shown in FIG. 19. By adding succeedingfields in order, it is possible to obtain a time and address informationnecessary for accessing desirable VOBU.

ISTREF_SZ

Number of packs from a VOBU head pack to a pack including last data ofthe head I picture in the VOBU is recorded therein.

VOBU_PB_TM

The reproducing time length of the VOBU is recorded therein.

VOBU_SZ

The data amount of the VOBU is recorded therein.

“S_AVFIT” (FIG. 20)

S_AVFIT (Still picture AV File Information Table) has managementinformation corresponding to the still picture AV file “RTR_STO.VRO”recorded therein, and comprises S_AVFITI, S_VOB_STI and S_AVFI.

“S_AVFITI” (FIG. 20)

S_AVFITI (Still Picture AV File Information Table Information) storesthe following information necessary for accessing S_VOB_STI and S_AVFI.

S_AVFI_Ns (Number of Still Picture AV File Information)

“0” or “1” is recorded therein as the S_AVFI number. This value alsocorresponds to the still picture AV file number, that is, the presenceof the RTR_STO.VRO file.

S_VOB_STI_Ns (Number of Still Picture VOB Stream Information)

Number of S_VOB_STI which will be described below is recorded therein.

S_AVFI_EA (Still Picture AV File Information End Address)

The end address of S_AVFI is recorded therein.

“S_VOB_STI” (FIG. 20)

In S_VOB_STI (Still Picture VOB Stream Information) is recorded thefollowing information as the stream information of the still pictureVOB.

V_ATR (Video Attribute)

Video compression mode, TV system, Aspect ratio, and Video resolutionare recorded therein as video attribute information. Individual fieldsare the same as V_ATR in the above-mentioned M_VOB_STI.

OA_ATR (Audio Stream Attribute)

Audio coding mode, Application Flag, Quantization/DRC, fs, and Number ofAudio channels are recorded as audio stream attribute information.Individual fields are the same as A_ATR0 in the above-mentionedM_VOB_STI.

SP_ATR (Sub-picture Attribute)

Application Flag is recorded therein as sub-picture attributeinformation. The field is the same as SP_ATR in the above-mentionedM_VOB_STI.

SP_PLT (Sub-picture Color Palette)

Color palette information for a sub-picture is recorded therein. Arecording format is the same as SP_PLT in the above-mentioned M_VOB_STI.

“S_AVFI” (FIG. 23)

S_AVFI (Still Picture AV File Information) comprises informationnecessary for accessing a still picture VOG, S_AVFI_GI, S_VOGI_SRP andS_VOGI.

“S_AVFI_GI” (FIG. 23)

S_AVFI_GI (Still Picture AV File information General Information) storesS_VOGI_SRP_Ns.

S_VOGI_SRP_Ns (Number of Still Picture VOB Group Search Pointer)

Number of fields of S_VOGI_SRP which will be described below is recordedtherein.

“S_VOGI_SRP” (FIG. 23)

S_VOGI_SRP (Static VOB Group Information Search Pointer) storesS_VOGI_SA.

The start address of S_VOGI is recorded in the S_VOGI_SA_SA (StillPicture VOB Group Information Start Address).

“S_VOGI” (FIG. 23)

The S_VOGI (Still Picture VOB Group Information) comprises themanagement information of the still picture VOB, S_VOGI_GI, S_VOB_ENTand CP_MNGI.

“S_VOG_GI” (FIG. 23)

The following information is recorded as the general information of astill picture VOB group in S_VOG_GI (Still Picture VOB Group GeneralInformation).

S_VOB_Ns (Number of Still Picture VOBs)

Number of still picture VOBs in the still picture VOB group is recordedtherein.

S_VOB_STIN (S_VOB_STI Number)

Recorded therein is S_VOB_STI number of S_VOB_STI which stores thestream information of the still picture VOB. The S_VOB_STI number is therecording order in the above-mentioned S_VOB_STI table.

FIRST_VOB_REC_TM (First VOB Recording Data and Time)

The recording date and time information of the first (head) stillpicture VOB in the still picture VOB group is recorded therein.

LAST_VOB_REC_TM (Last VOB Recording Data and Time)

The recording date and time information of the last still picture VOB inthe still picture VOB group is recorded therein.

S_VOB_SA (Still Picture VOB Group Start Address)

The start address of the still picture VOB group in the RTR_STO.VRO fileis recorded therein.

“CP_MNGI”

CP_MNGI (Copy Management Information) stores copy management informationrelated to the still picture VOB group. Individual fields are the sameas the CP_MNGI of the above-mentioned M_VOBI.

“S_VOB_ENT” (FIG. 24)

S_VOB_ENT (Still Picture VOB Entry) corresponds to individual stillpicture VOBs in the still picture VOB group, and is divided into thefollowing types A and B depending on the presence of audio data.

“S_VOB_ENT (Type A)” (FIG. 24)

The type A comprises S_VOB_ENT_TY and V_PART_SZ. Individual fields areas follows.

S_VOB_ENT_TY (Still Picture VOB Entry Type)

The type information of the still picture VOB is recorded therein in aformat shown in FIG. 25.

MAP_TY

Any one of the following values for identifying the type A or the type Bis recorded therein.

00b: Type A

01b: Type B

TE

Any one of the following values for identifying the status of the stillpicture VOB is recorded therein.

0b: Normal status

1b: Temporary erasing status

SPST_Ns

Number of sub-picture streams in the still picture VOB is recordedtherein.

V_PART_SZ (Video Part Size)

The data amount of the still picture VOB is recorded therein.

“S_VOB_ENT (Type B)” (FIG. 24)

The type B has A_PART_SZ and A_PB_TM in addition to S_VOB_ENT_TY andV_PART_SZ. Individual fields are as follows.

S_VOB_ENT_TY (Still Picture VOB Entry Type)

The type information of the still picture VOB is recorded therein.Individual fields are the same as the above-mentioned type A.

V_PART_SZ (Video Part Size)

The data amount of a video part in the still picture VOB is recordedtherein.

A_PART_SZ (Audio Part Size)

The data amount of an audio part in the still picture VOB is recordedtherein.

A_PB_TM (Audio Reproducing Time)

The reproducing time length of the audio part of the still picture VOBis recorded.

“UD_PGCIT” (FIG. 26)

UD_PGCIT (User-Defined PGC Information Table) comprises UD_PGCITI,UD_PGCI_SRP and UD_PGCI.

“UD_PGCITI” (FIG. 26)

UD_PGCITI (User-Defined PGC Information Table Information) stores thefollowing information constituting the user-defined PGC informationtable.

UD_PGCI_SRP_Ns (Number of User-Defined PGC Information Search Pointers)

Number of UD_PGCI_SRP is recorded therein.

UD_PGCIT_EA (User-Defined PGC Information Table End Address)

The end address of UD_PGCIT is recorded therein.

“UD_PGCI_SRP” (FIG. 26)

UD_PGCI_SA is recorded in UD_PGCI_SRP (User-Defined PGC InformationSearch Pointer).

UD_PGCI_SA (User-Defined PCG Information Start Address)

The start address of UD_PGCI is recorded in UD_PGCI_SA. A seek iscarried out up to a recorded address when the PGCI is accessed.

“UD_PGCI” (FIG. 26)

The details of the UD_PGCI (User-Defined PGC Information) will bedescribed in the following PGCI.

“O_PGCI” (FIG. 5)

The details of O_PGCI (Original PGC Information) will be described inthe following PGCI.

“TXTDT_MG” (FIG. 27)

TXTDT_MG (Text Data Management) comprises TXTDTI, IT_TXT_SRP and IT_TXT.Individual fields are as follows.

“TXTDTI” (FIG. 27)

TXTDTI (Text Data Information) comprises CHRS, IT_TXT_SRP_Ns andTXTDT_MG_EA.

CHRS (Character Set Code)

A character set code to be used for the IT_TXT is recorded therein.

IT_TXT SRP_Ns (Number of IT_TXT Search Pointers)

Number of the IT_TXT_SRP is recorded therein.

TXTDT_MG_EA (Text Data Management End Address)

The end address of the TXTDT_MG is recorded therein.

“IT_TXT_SRP” (FIG. 27)

IT_TXT_SRP (IT_TXT Search Pointer) stores the following as accessinformation to corresponding IT_TXT.

IT_TXT_SA (IT_TXT Start Address)

The start address of the IT_TXT is recorded therein. When the IT_TXT isaccessed, a seek is carried out up to this address.

IT_TXT_SZ (IT_TXT Size)

The data size of the IT_TXT is recorded therein. When the IT_TXT is tobe read, data with only this size is read.

“IT_TXT” (FIG. 27)

The IT_TXT comprises a plurality of sets or one set, each set havingIDCD (identification code), TXT (text) corresponding to the IDCD andTMCD (termination code). When there is no TXT corresponding to the IDCD,the IDCD and the TMCD may make a set without TXT. The IDCD is defined asfollows.

Genre Code

30h: Movie

31h: Music

32h: Drama

33h: Animation

34h: Sports

35h: Documentary

36h: News

37h: Weather

38h: Education

39h: Hobby

3Ah: Entertainment

3Bh: Art (play, opera)

3Ch: Shopping

Input Source Code

60h: Broadcasting station

61h: Camcorder

62h: Photograph

63h: Memo

64h: Others

“PGCI” (FIG. 28)

PGCI (PGC Information) has a data structure which is common to O_PGCIand UD_PGCI, and comprises PGC_GI, PGI, CI_SRP and CI.

“PGC_GI” (FIG. 28)

PGC_GI (PGC_General Information) comprises PG_Ns and CI_SRP_Ns as thePGC general information. Individual fields are as follows.

PG_Ns (Number of Programs)

Number of programs in the PGC is recorded therein. For the user-definedPGC, “0” is recorded in this field because the user-defined PGC has noprogram.

CI_SRP_Ns (Number of CI_SRP)

Number of CI_SRP which will be described below is recorded.

“PGI” (FIG. 28)

PGI (Program Information) comprises PG_TY, C_Ns, PRM_TXTI, IT_TXT_SRPNand THM_PTRI. Individual fields are as follows.

PG_TY (Program Type)

The following information indicative of the status of this program isrecorded therein by using a format shown in FIG. 29.

Protect (Protect)

0b: Normal status

1b: Protect status

C_Ns (Number of Cells)

Number of cells in this program is described.

PRM_TXTI (Primary Text Information)

Text information indicative of the contents of this program is recordedtherein. The details are the same as in the above-mentioned PL_SRPT.

IT_TXT_SRPN (IT_TXT_SRP Number)

In the case where information indicative of the contents of this programis optionally recorded as the IT_TXT in addition to the abovementionedprimary text, the number of IT_TXT_SRP recorded in the TXTDT_MG isrecorded in this field.

THM_PTRI (Thumb Nail Pointer Information)

Thumb nail information which is representative of this program isdescribed therein. The details of THM_PTRI are the same as in theTHM_PTRI of the above-mentioned PL_SRPT.

“CI_SRP” (FIG. 28)

CI_SRP (Cell Information Search Pointer) stores address information foraccessing the cell information.

CI_SA (Cell Information Start Address)

The start address of the cell information is recorded therein. In thecase where the cell is accessed, a seek is carried out up to thisaddress.

“CI” (FIG. 30)

CI (Cell Information) is classified into MI_CI for a motion picture andS_CI for a still picture.

“M_CI” (FIG. 30)

M_CI (Motion picture Cell Information) comprises M_C_GI and M__EPI.

“M_C_GI” (FIG. 30)

M_C_GI (Motion picture Cell General Information) has the following basicinformation constituting a cell.

C_TY (Cell Type)

The following information for identifying a motion picture cell and astill picture cell are recorded in a format shown in FIG. 31.

C_TY1

000b: Motion Picture (Movie) Cell

001b: Still Picture Cell

M_VOBI_SRPN (Movie VOB Information Search Pointer Number)

The search pointer number of movie VOB information to which this cellcorresponds is recorded therein. In the case where access is to be givento stream data to which this cell corresponds, access is first given toa movie VOB information search pointer number indicated by this field.

C_EPI_Ns (Number of Cell Entry Point Information)

Number of entry point present in this cell is recorded therein.

C_V_S_PTM (Cell Video Start Time)

The reproducing start time of this cell is recorded in a format shown inFIG. 10.

C_V_E_PTM (Cell Video End Time)

The reproducing end time of this cell is recorded in the format shown inFIG. 10. The effective interval of this cell in the VOB to which thiscell corresponds is specified by using the C_V_S_PTM and C_V_E_PTM.

“M_C_EPI” (FIG. 32)

M_C_EPI (Motion Picture Cell Entry Point Information) is classified intoa type A and a type B depending on the presence of a primary text.

“M_C_EPI (Type A)” (FIG. 32)

M_C_EPI (Type A) comprises the following information indicative of anentry point.

EP_TY (Entry Point Type)

The following information for identifying the type of this entry pointis recorded in accordance with a format shown in FIG. 33.

EP_TY1

00b: Type A

01b: Type B

EP_PTM (Entry Point Time)

A time that the entry point is put is recorded in accordance with theformat shown in FIG. 10.

“M_C_EPI (Type B)” (FIG. 32)

M_C_EPI (Type B) has the following PRM_TXTI in addition to the EP_TY andEP_PTM included in the type A.

PRM_TXTI (Primary Text Information)

Recorded therein is text information indicative of the contents oflocations indicated by this entry point. The details are the same as inthe above-mentioned PL_SRPT.

“S_CI” (FIG. 30)

S_CI (Still Picture Cell Information) comprises S_C_GI and S__EPI.

“S_C_GI” (FIG. 30)

S_C_GI (Still Picture Cell General Information) has the following basicinformation constituting a cell.

C_TY (Cell Type)

Information for identifying a motion picture cell and a still picturecell are recorded. The details are the same as in the above-mentionedmotion picture cell.

S_VOGI_SRPN (Still Picture VOB Group Information Search Pointer Number)

Recorded therein is the search pointer number of still picture VOB groupinformation to which this cell corresponds. In the case where access isto be given to stream data to which this cell corresponds, access isfirst given to a still picture VOB group information search pointernumber indicated by this field.

C_EPI_Ns (Number of Cell Entry Point Information)

Number of entry points present in this cell is recorded.

S_S_VOB_ENTN (Start Still Picture VOB Number)

The reproducing start still picture VOB number of this cell is recordedin the format shown in FIG. 11. The still picture VOB number is theorder in the S_VOG indicated by the above-mentioned S_VOGI_SRPN.

E_S_VOB_ENTN (End Still Picture VOB Number)

The reproducing end still picture VOB number of this cell is recorded inthe format shown in FIG. 11. The still picture VOB number is the orderin the S_VOG indicated by the above-mentioned S_VOGI_SRPN. The effectiveinterval of this cell in the S_VOG to which the cell corresponds isspecified by using the S_S_VOB_ENTN and E_S_VOB_ENTN.

“S_C_EPI” (FIG. 32)

S_C_EPI (Still Picture Cell Entry Point Information) is classified intoa type A and a type B depending on the presence of a primary text.

“S_C_EPI (Type A)” (FIG. 32)

S_C_EPI (Type A) comprises the following information indicative of anentry point.

EP_TY (Entry Point Type)

The following information for identifying the type of this entry pointis recorded in accordance with a format shown in FIG. 33.

EP_TY1

00b: Type A

01b: Type B

S_VOB_ENTN (Still Picture VOB Entry Number)

A number of still picture on which an entry point is put is recordedtherein in accordance with the format shown in FIG. 11.

“S_C_EPI (Type B)” (FIG. 32)

S_C_EPI (Type B) has the following PRM_TXTI in addition to the EP_TY andS_VOB_ENTN included in S_C_EPI of type A.

PRM_TXTI (Primary Text Information)

Recorded therein is text information indicative of the contents oflocations indicated by this entry point. The details are the same as inthe above-mentioned PL_SRPT.

(DVD Recorder)

Next, the structure of the DVD recorder in this embodiment will bedescribed.

The DVD-recorder of this embodiment has almost the same structure as theone of the first embodiment but differs in the following point. That is,in the DVD-recorder, the system controller 7802 includes anafter-recording check section 78021 and an after-recording operationsection 78022 for performing after-recording as shown in FIG. 53.

Though the operation of the recorder of this embodiment is almost sameas in the first embodiment, a significant difference is that theafter-recording check section 78021 in the recorder of this embodimentchecks in advance whether the recorder has an ability to performafter-recording for an audio stream which is intended to beafter-recorded.

As described above, the optical disc of this embodiment has bit rateinformation (“Bitrate”) as attribute information of a dummy audio streamprovided for after-recording in addition to audio coding modeinformation, and information of number of audio channels.

With reference to the audio attribute information, the DVD recorderchecks in advance whether or not the recorder can perform anafter-recording operation by using the dummy audio stream.

Concretely, it is determined whether the after-recording operation ispossible or not by comparing audio coding mode, audio channel number andbit rate with an encode ability of the DVD recorder.

When the after-recording operation is determined to be possible, theafter-recording operation is performed as in the first embodiment. Whenthe after-recording operation is determined to be impossible, the useris notified that the after-recording operation is impossible via theuser interface 7801 in a predetermined manner (for example, to displaymessage). This operation is described below with reference to flowcharts in FIGS. 54, 55 and 56.

Referring to FIG. 54, upon receiving a user request for after-recordingto a desired program (PG) via the user interface 7801 (S1), the systemcontroller 7802 reads in movie VOB information (M_VOBI) and movie VOBstream information (M_VOB_STI) related to the designated program (PG)(S2). Then, the possibility of an after-recording operation in therecorder is checked (S3). That is, it is determined whether or not theafter-recording operation is possible with reference to M_VOBI andM_VOB_STI (S3). With the result, when the after-recording operation isdetermined to be possible (S4), the controller starts theafter-recording operation (S5). When the after-recording operation isdetermined to be impossible (S4), the controller notifies the user thatthe after recording operation is impossible (for example, displaysmessage) (S6).

The check routine of the possibility of the after-recording operation(step S3) is performed as follows in accordance with the flowchart ofFIG. 55.

The controller checks number of audio streams based on AST_Ns ofM_VOB_STI (in FIG. 12) (S31). When there are two audio streams (S32),attribute of each audio stream is checked or determined whether or noteach audio stream is in a state where it is possible to perform theafter-recording operation to the stream (referred to as“after-recordable state”) (S33). Details of this process will bedescribed later. With the result of the check, when the audio stream isin after-recordable state (S34), coding mode (“Audio Coding Mode”) (seeFIG. 13) in A_ATR1 of M_VOB_STI is checked (S35). When an encoder of theDVD recorder is operable in the checked coding mode (S36), bit rate(“Bitrate”) in A_ATR1 of M_VOB_STI is checked (S37). When the encoder isoperable in the checked bit rate (S38), it is decided that theafter-recording operation is “possible” (S39). Otherwise, it is decidedthat an after-recording operation is “impossible” (S40).

The check routine of attribute of audio stream (step S33) is performedas follows in accordance with the flowchart in FIG. 56.

Firstly, it is determined whether the A1_STATUS of audio stream forafter-recording (audio stream 2) (see FIG. 17) is in “dummy state forafter-recording” (S321). When the A1_STATUS is in “dummy state forafter-recording”, the audio stream is decided to be in “after-recordablestate” (S322). It is noted that “dummy state for after-recording”indicates that the audio stream is prepared for after-recording but thatafter-recording data have not been recorded yet in the audio stream.When the A1_STATUS is not in “dummy state for after-recording”, noticeis served to user that the audio stream has already been after-recorded,and user's response is waited (S323). When after-recording is ordered byuser in the response (S324), the audio stream is decided to be inafter-recordable state (S322). When after-recording is not ordered byuser in the response (S324), the audio stream is decided not to be inafter-recordable state (S325).

The DVD recorder according to this embodiment creates the managementinformation for each motion picture recording. The DVD recorderespecially creates audio coding mode, number of audio channels and bitrate information as an audio stream attribute information, and recordsthem onto the optical disc.

While in this embodiment the recorder is provided for the DVD-RAM disc,this invention is not limited to DVD-RAM but applicable to re-writabledisc.

While in this embodiment details of data structure on the disc isdescribed, the data structure is not limited to the structure describedabove. That is, this invention can be implemented by the recorder thatcompares audio attribute information including bit rate with encodingability in advance when the recorder performs after-recording.

While in this embodiment the description is made for two audio streams,same advantage could be obtained when only one audio stream is recordedas in the case where two audio streams are recorded.

Although the present invention has been described in connection withspecified embodiments thereof, many other modifications, corrections andapplications are apparent to those skilled in the art. Therefore, thepresent invention is not limited by the disclosure provided herein butlimited only to the scope of the appended claims.

What is claimed is:
 1. An information recording medium comprising anarea for storing at least one video object and an area for storingmanagement information, wherein: the video object includes a videostream which is obtained by coding a video signal, a first audio streamwhich is obtained by coding an audio signal and a second audio streamwhich is obtained by coding an audio signal; the management informationcomprises a first management information and a second managementinformation; the first management information includes at least onestream information, the stream information includes a bit rate of thefirst audio stream, bit rate of the second audio stream, number of audiostreams included in the video object, coding mode of the first audiostream, and coding mode of the second audio stream; the secondmanagement information stores management information for the videoobject that includes a status information and a specified number, thestatus information indicates whether or not the second audio stream isprovided for after-recording operation, and whether or not theafter-recording data is recorded to the second audio stream when thesecond audio stream is provided for after-recording operation, and thespecified number designates one of the stream information correspondingto the video object.
 2. An information recording apparatus forperforming after-recording to the second audio stream included in thevideo object stored on the information recording medium according toclaim 1, the apparatus comprising: checking section for checking inadvance whether or not the apparatus is operable to performafter-recording to the second audio stream based on at least the statusinformation and the bit rate included in the management informationbefore the after-recording operation; and starting section for startingafter-recording operation when it is decided by the checking sectionthat the apparatus is operable to perform after-recording to the secondaudio stream.
 3. The apparatus according to claim 2, wherein thechecking section comprises: a first determining section for determiningwhether or not the second audio stream is in a status where theafter-recording operation can be done with reference to the statusinformation of the second audio stream included in the managementinformation; a second determining section for determining whether or notthe apparatus is able to encode the second audio stream with referenceto the bit rate of the second audio stream included in the managementinformation; and a third determining section for determining that theapparatus is able to perform after-recording when it is determined thatthe second audio stream is in the status where the after-recordingoperation can be done and that the apparatus is able to encode thesecond audio stream.
 4. The apparatus according to claim 3, wherein thechecking section further comprises a notifying section for notifying auser that after-recording operation is impossible when the thirddetermining section determines that the apparatus is not able to performafter-recording.
 5. The apparatus according to claim 3, wherein when themanagement information further comprises the number of audio streamsincluded in the video object, the first determining section makes thedetermination with reference to the number of audio streams in additionto the status information.
 6. The apparatus according to claim 3,wherein when the management information further comprises coding mode ofthe second audio stream, the second determining section determineswhether or not the apparatus can encode the second audio stream withreference to the coding mode of the second audio stream in addition tothe bit rate of the second audio stream.
 7. A method for performingafter-recording to the second audio stream recorded on the recordingmedium according to claim 1 by using a recording apparatus, the methodcomprising: checking in advance whether or not the apparatus is operableto perform after-recording to the second audio stream based on at leastthe status information and the bit rate included in themanagement-information before the after-recording operation; andstarting after-recording operation when it is decided by the checkingthat the apparatus is operable to perform after-recording to the secondaudio stream.
 8. The method according to claim 7, wherein the checkingcomprises: first determining whether or not the second audio stream isin a status where the after-recording operation can be done withreference to the status information of the second audio stream includedin the management information; second determining whether or not theapparatus is able to encode the second audio stream with reference tothe bit rate of the second audio stream included in the managementinformation; and third determining that the apparatus is able to performafter-recording when it is determined that the second audio stream is inthe status where the after-recording operation can be done and that theapparatus is able to encode the second audio stream.
 9. The methodaccording to claim 8, wherein the checking further comprises notifying auser that after-recording operation is impossible when by the thirddetermining it is determined that the apparatus is not able to performafter-recording.
 10. The method according to claim 8, wherein when themanagement information further comprises the number of audio streamsincluded in the video object, the first determining makes thedetermination with reference to the number of audio streams in additionto the status information.
 11. The method according to claim 8, whereinwhen the management information further comprises coding mode of thesecond audio stream, the second determining determines whether or notthe apparatus can encode the second audio stream with reference to thecoding mode of the second audio stream in addition to the bit rate ofthe second audio stream.
 12. A reproduction apparatus for reproducinginformation recorded in the information recording medium according toclaim
 1. 13. An information recording medium comprising: an areaoperable to store at least one video object and an area operable tostore management information; wherein the video object comprises a videostream which is obtained by coding a video signal, a first audio streamwhich is obtained by coding an audio signal, and a second audio streamwhich is obtained by coding an audio signal; wherein the managementinformation comprises a first management information and a secondmanagement information; wherein the first management informationcomprises at least one stream information, the stream informationcomprises bit rate of the first audio stream, bit rate of the secondaudio stream, number of audio streams included in the video object,coding mode of the first audio stream, and coding mode of the secondaudio stream; and wherein the second management information comprisesmanagement information for the video object that includes a statusinformation and a specified number, the status information operable toindicate whether or not the second audio stream is provided forafter-recording operation, and operable to indicate whether or not theafter-recording data is recorded to the second audio stream when thesecond audio stream is provided for after-recording operation, and thespecified number is operable to designate one of the stream informationcorresponding to the video object.
 14. An information recordingapparatus for performing after-recording to the second audio streamincluded in the video object stored on the information recording mediumaccording to claim 13, said information recording apparatus comprising:checking section operable to check in advance whether or not saidinformation recording apparatus is operable to perform after-recordingto the second audio stream based on at least the status information andthe bit rate included in the management information before theafter-recording operation; and starting section operable to start theafter-recording operation when it is decided by said checking sectionthat said information recording apparatus is operable to performafter-recording to the second audio stream.
 15. An information recordingapparatus as claimed in claim 14, wherein said checking sectioncomprises: a first determining section operable to determine whether ornot the second audio stream is in a status where the after-recordingoperation can be performed with reference to the status information ofthe second audio stream included in the management information; a seconddetermining section operable to determine whether or not saidinformation recording apparatus is able to encode the second audiostream with reference to the bit rate of the second audio streamincluded in the management information; and a third determining sectionoperable to determine that said information recording apparatus is ableto perform after-recording when it is determined that the second audiostream is in the status where the after-recording operation can beperformed and that said information recording apparatus is able toencode the second audio stream.
 16. An information recording apparatusas claimed in claim 15, wherein said checking section further comprisesa notifying section operable to notify a user that the after-recordingoperation is impossible when said third determining section determinesthat said information recording apparatus is not able to performafter-recording.
 17. An information recording apparatus as claimed inclaim 15, wherein said first determining section is operable to make thedetermination with reference to the number of audio streams included inthe video object in addition to the status information.
 18. Aninformation recording apparatus as claimed in claim 15, wherein saidsecond determining section is operable to determine whether or not saidinformation recording apparatus can encode the second audio stream withreference to the coding mode of the second audio stream in addition tothe bit rate of the second audio stream.
 19. A method for performingafter-recording to the second audio stream recorded on the informationrecording medium according to claim 13 by using a recording apparatus,said method comprising: checking in advance whether or not the recordingapparatus is operable to perform after-recording to the second audiostream based on at least the status information and the bit rateincluded in the management information before the after-recordingoperation; and starting the after-recording operation when it is decidedby said checking that the recording apparatus is operable to performafter-recording to the second audio stream.
 20. A method as claimed inclaim 19, wherein said checking comprises: first determining whether ornot the second audio stream is in a status where the after-recordingoperation can be performed with reference to the status information ofthe second audio stream included in the management information; seconddetermining whether or not the recording apparatus is able to encode thesecond audio stream with reference to the bit rate of the second audiostream included in the management information; and third determiningthat the recording apparatus is able to perform after-recording when itis determined that the second audio stream is in the status where theafter-recording operation can be performed and that the recordingapparatus is able to encode the second audio stream.
 21. A method asclaimed in claim 20, wherein said checking further comprises notifying auser that the after-recording operation is impossible when by said thirddetermining it is determined that the recording apparatus is not able toperform after-recording.
 22. A method as claimed in claim 20, whereinsaid first determining makes the determination with reference to thenumber of audio streams included in the video object in addition to thestatus information.
 23. A method as claimed in claim 20, wherein saidsecond determining determines whether or not the recording apparatus canencode the second audio stream with reference to the coding mode of thesecond audio stream in addition to the bit rate of the second audiostream.
 24. A reproduction apparatus for reproducing informationrecorded in the information recording medium according to claim 13.